1. Field of the Invention
This invention relates to a spring structure for a pressure plate of a photographic camera for urging toward a film the pressure plate which is mounted on a camera back to be movable in the direction of the optical axis of the taking lens of the camera.
2. Description of the Prior Art
There has been known a spring structure for a pressure plate of a photographic camera in which the pressure plate is urged by a plate spring member interposed between the pressure plate and the camera back body.
There also has been known a spring structure for a pressure plate of a photographic camera in which the pressure plate is urged by a plurality of compression coil springs interposed between the pressure plate and the camera back body to extend in the direction of the optical axis of the taking lens of the camera.
Recently electronic circuit parts, switches, external displays or the like such as for recording date or the like has come to be disposed on the camera back.
In the former spring structure, a space corresponding to the thickness of the plate spring member plus a margin for permitting deformation of the plate spring member is necessary substantially over the entire area of the pressure plate, which adds to the size from the film surface to the outer surface of the camera back and obstructs miniaturization of the camera body.
Also in the latter spring structure, a space corresponding to the length of the coil springs is necessary in the direction of the optical axis and a space corresponding to the diameters of the coil springs is necessary in the direction perpendicular to the optical axis. It also obstructs miniaturization of the camera body.
Especially, in the case of a camera back where electronic circuit parts, switches, external displays or the like such as for recording date or the like are disposed, the plate spring member or the coil springs are arranged on the camera back together with those parts, which makes further difficult miniaturization of the camera body and can deteriorate appearance of the camera body.